An underwater cage is susceptible to vegetation or algae growth which is fairly easy to remove if all sides of the cage material are periodically scrubbed. Fouling on an aquaculture screen is progressive in nature. Frequent cleaning of the earlier stages of growth help to prevent the growth from reaching later stages of hard growth that becomes progressively difficult to remove. Current cage cleaning methods are simple conventional brush devices used by hand or are power driven. The bending brush bristles can only contact about one-quarter to one-third of the strands at one pass. A second pass in the other direction will affect an additional one-quarter to one-third of the screen stand surface for cleaning. For a complete screening of the opposite side of the screen, the opposite side must also be brushed thereby doubling the cleaning effort.
Also used in the aquaculture industry are high pressure water cleaners. They are 15 to 60 horsepower, with larger units requiring a barge, crane and two operators. This expense is prohibitive for most aquaculture farms and is not suitable for farming offshore where the sea conditions make this type of equipment unusable. Current cage cleaner designs are typically corded and require robust power supplies, typically in the form of a generator on a barge. Aquaculture cages vary from site to site and manufacturer to manufacturer. Most have unique geometries that could pose a problem with corded devices where the cord could tangle with the internal geometry of the cage. Some current and expired technologies have been developed that are smaller electric or hydraulic powered devices. These have not been successful in the industry because conventional brushes do not work well enough and several passes on both sides of the screen are required for complete cleaning.
Additionally, almost all aquaculture cages have structure or corners that prevent the use of automated cage cleaning devices. Attempts to solve this problem have utilized robotics with tractor drives and live video for remote control. This comes at a very high cost and a human operator is also required.